What Types of Profiles Are Used in PVC Windows?
Number of chambers, depth, gaskets, reinforcement and profile shapes: understanding PVC window frames to make a better choice.
Behind the term “PVC window” lie very different profiles. Their design affects insulation, stiffness, glazing options and appearance. Here is how to find your way around.
Number of chambers
A PVC profile is hollow and divided into chambers. Each creates an air pocket that slows heat flow.
- Older profiles often had three chambers.
- Current profiles usually have five to seven, for better insulation.
The chamber count is only an indicator, though: the Uw value of the complete window is what allows comparison.
Profile depth
Commonly between about 70 and 85 mm. A deeper profile can take thicker glazing, such as acoustic units or triple glazing, and leaves more room for insulating chambers.
Gasket systems
- Two gaskets (one on the sash, one on the frame): the most common set-up.
- Three gaskets, with a central seal: better airtightness and sound insulation.
Reinforcement
A central chamber houses a reinforcement, usually galvanised steel. It stiffens large sizes and gives hardware a solid hold. Some manufacturers use more insulating composite reinforcements.
Shapes and finishes
- Square profile: clean, modern lines.
- Sculpted or moulded profile: a more classic look for older buildings.
- Foil finish: decorative wood-effect or colour film on one or both faces.
- Through-coloured or lacquered: for colours, with dedicated ranges for dark shades in the sun.
Renovation profiles
Some frames are designed to be fitted over the old frame, with cover flanges that conceal the junction. They avoid masonry work but slightly reduce the glass area.
In short
Chambers, depth, gaskets and reinforcement determine a PVC window’s performance. Ask for the profile system’s data sheet, and always compare on Uw, AEV rating and installation quality.